Conventionally, there exist combined hot water supply and air-conditioning devices capable of simultaneously providing a cooling load, a heating load, and a hot water supply load by means of a single-stage refrigeration cycle. As such a device, there has been proposed “a multifunctional heat pump system including a single compressor, and configured by a refrigerant circuit that connects the compressor, a heat source unit-side heat exchanger, a use-side heat exchanger, a cooling energy storage tank, and a hot water supply heat exchanger, in which refrigerant flows to the respective heat exchangers are switched, thereby forming a refrigeration cycle that enables an independent operation of cooling and heating/hot water supply/heat storage/cold storage and a combined operation of those operations” (see, for example, Patent Literature 1).
There also exist combined hot water supply and air-conditioning devices capable of simultaneously providing high-temperature hot water supply and an indoor air-conditioning function by means of a two-stage refrigeration cycle. As such a device, there has been proposed “a heat pump-type hot water supply device including: a refrigerant circuit on the low stage side through which a first refrigerant is made to flow and in which a first compressor, a refrigerant distributing device, a first heat exchanger, a second heat exchanger, a first expansion device, a heat source unit-side heat exchanger, a four-way valve, and the first compressor are connected in this order, and from the refrigerant distributing device, the four-way valve, a use-side heat exchanger, and a second expansion device are interposed in this order and connected between the second heat exchanger and the first expansion device; a refrigerant circuit on the high stage side through which a second refrigerant flows and in which a second compressor, a condenser, a third expansion device, the first heat exchanger, and the second compressor are connected in this order; and a hot water supply path through which water for hot water supply is made to flow and in which the second heat exchanger and the condenser are connected in this order” (see, for example, Patent Literature 2).